Your thermostat was stuck in the open position, which it was designed to do.
Notice once again, no mention of the water tube grommet. Almost guarantee that part is toast. Your engine may cool somewhat from this point on but will have a built in restriction to water flow from now on. Look at it like a water hose with a partial kink in it.
Please Please, heed Pappy's advice on this. I know it seems like a big chore, but investigating will insure your motor cools properly and that you will visually see the condition of both water grommets.
Here a couple of links that will help walk you through the process and gives pictures and explanations.
Lower unit
https://www.leeroysramblings.com/Lower_unit.htm
Water Circulation & Associated Problems (please through this link very well)
